Drawing

Object Detail

These drawings were produced in 1842 by P. Dall, R.N. They formed part of a proposal for a time ball to be erected at the Observatory on Calton Hill in Edinburgh. Time balls were used to provide sailors with an accurate visual time signal. Chronometers could be set at precisely one o’clock, when the ball dropped on a column at the top of the tower.
The time ball now on top of the Nelson Monument at Calton Hill was set up by the clockmaker Frederick James Ritchie and Professor Charles Piazzi Smyth, Edinburgh’s second Astronomer Royal. The Corporation of Trinity House had a keen interest in time-keeping and navigation.